I currently have BW v.2026.5.1 in Firefox, and I don’t see any slowness. Even with v.2026.5.0 and v.2026.4.0, I didn’t have any problems with sites/logins. The only noticeable bug was on the saving of autofill settings, which was fixed in v.2026.5.0.
Disclaimer: I’m a developer, and I use very powerful PCs.

If other people are still complaining, it may be one (or more!) of the following things:
- They have a slow or very low-end PC
- They have a compromised PC
- They use some particular, specific sites, e.g., Reddit (?) (I don’t use it, so I can’t tell), which may still be problematic with BW